Notorious womanizer Max (David Schwimmer) is in shock. Chicago’s favorite TV sportscaster has known the lovely, literary Sam (Mili Avital) less than 24 hours and already he is ready spend the rest of his life with her. Three weeks later, Max is suddenly confronted with the reality that this will be the last woman he will ever sleep with.

Desperately trying to discover how he can know if he has met the right person before she wreaks havoc on a major portion of his life, he turns to his best friend Jay (Jason Lee). Max asks Jay to help him find out by testing Sam to see if she would cheat on him. But as Max pursues his scheme, he brings about the very mishaps and miscommunications that will finally make his self-absorbed heart unfold.